Incendiary
by ShamelessDilettante
Summary: In which Tsuna is an amalgamation of Flame and /flame/ and canon is ditched early on. And the only thing Reborn can do when he gets a letter from Vongola is /laugh/. Dabble Style. R27, and tons of backstory. Not in chronological order.
1. Chapter 1

**Summary:**

In which Tsuna is an amalgamation of Flame and _flame_ and canon is ditched early on.

And the only thing Reborn can do when he gets a letter from Vongola is _laugh._

 **Warnings (?):** Not in chronological order as I'm pretty much writing and posting whenever. Drabble Style (so, short chapters). Reborn x Tsuna later... is what I would say but I might write a chapter ten years after they got together, or I'll write one ten years before they get together. Liberties taken with canon-verse lore.

 **A/N:** This fic is a monster formed from two things: an urge to write R27, and pyro!Tsuna. Enjoy. (On another note, I have _got_ to stop stress writing. )

 **Disclaimer:** KHR belongs to Amano Akira.

* * *

 _Dear Reborn,_

 _If you are receiving this, then I have died ahead of time._

 _I endeavour to request a favour, for I cannot order you as you aren't an official part of my beloved famiglia, but I have known you since childhood and can only hope that will be enough._

 _My son is still too young to take up the mantle, and many already disapprove of his sickly nature. Unfortunately, only those with the blood of Vongola may wear the Sky ring. What you may not know is, Uncle Iemitsu, yes the 'blond idiot' as you like to call him, is actually a direct descendant of Vongola Primo._

 _Now, back to my request. A few years ago, I discovered a secret stash of files my father had sealed. They contained highly sensitive information including Xanxus' parentage, Iemitsu's ancestry, and information on Iemitsu's lost son. That's right, a hidden Vongola prince._

 _I am reluctant to bring a civilian into this life, but Vongola needs a change, and there is no one else but my child who I refuse to let be manipulated until he is strong enough to fend for himself._

 _Therefore, I would be forever grateful if you could find this child -or young adult, I suppose, depending on when you receive this- and teach him as you taught Dino._

 _Enclosed is what little information is provided, concerning the location of Iemitsu's ex-wife and possible location of this Tsunayoshi._

 _Best regards,_

 _Enrico di Vongola,_  
 _Vongola Decimo_

* * *

Reborn read through the letter again, just to make sure he wasn't going senile or something.

Nope, content was exactly as his almost eidetic memory could read through the letter again, just to make sure he wasn't going senile or something.

Then he threw back his head. And _laughed_.

Tsuna poked his head through the door, watched Reborn bust a gut, then shook his head and went back to what he was doing with a muttered, "it was only a matter of time, anyway."

He yelped when the laughing stopped abruptly and a bullet lodged itself into the wall an inch away from his nose.

"I _heard_ that, Tsuna."


	2. Chapter 2

_Tsuna (2)_

Kawahira watched, bemused as the child, baby practically, pulled himself up and into his lap with only his little arms for support.

The fluffy head bobbed as the child peered curiously into his half eaten bowl of ramen.

Then Vongola Primo's progeny looked up and smiled, soft and well _-cute_ for lack of better term- and the not-human couldn't help smiling, if somewhat enigmatically, back.

Then his ramen burst into flames.

Oh.

 _Oh._

By the time Nana found her wayward child, he was safe and giggling to himself over pile of ash as he chanted something that vaguely sounded like 'Uncle-River*!' She breathed a sigh of relief and hoped that her baby hadn't burnt something important.

* * *

(Kawa (川) = River)


	3. Chapter 3

_Tsuna (2)_

The first time little Tsuna tripped on his stuffed carrot, he set his stuffed fish (a present from a certain missing man) ablaze.

Nana recognised the signs immediately.

It was somewhat a secret but her family had always been somewhat fire-aligned. As in; miraculously-setting-stuff-on-fire-according-to-their-whims-aligned. He great great great grandfather had been a notorious arsonist after all, and even she had a phase somewhere in high school (there was a reason the Hibaris went out of their way to ensure the warehouse district on the outskirts of Namimori were devoid of combustibles).

What she didn't know, and what Tsuna later was told, was that Nana Kasai was a descendant of one of those alien existences that came and gifted the earth with the precious artifacts that kept the world intact. Unlike Sepira who could see the future, her ancestor was the originator and very embodiment of flames; both real and willed.

The power had, or course, diluted over the course of many centuries, which was why Nana was rather surprised when her little baby boy set his silly fish toy aflame and proceeded to giggle and try to put it in his mouth.

Nana first lit a candle when she was twelve, and really, the ability was more a party trick than anything else -unless, of course, you were smart about it (recalling the warehouse incident, Nana felt a nostalgic thrill down her spine).

Tsuna hiccupped, a plume of smoke coming out of his mouth and waved his flaming toy up at his mama.

Nana smiled as she took the toy and _willed_ the flames out, always so much easier than lighting one, unlike her famous arsonist-grandfather whose inclination to setting fires really didn't translate into putting them out. It wasn't salvageable, but Tsuna never liked the toy anyway. But it seemed she would have to somehow teach her boy some control, lest he unsuspectingly hurt someone.

It turned into an epic battle of wills; Tsuna's kidnapped Captain Carrot versus Adorable Puppy Dog Eyes. Many dolls were sacrificed; about five Barbies became little more than plastic goo, a number of toy robots were reduced to ashes, and a slinky was heated and turned into a colourful wire scribble sculpture. Nana never got her little Tsu-kun to stop setting fire to people, but she did manage to mitigate the effects so people wouldn't be harmed _too badly_.

(Fast forward a few years, and Hana would question what was _with_ Tsuna adding fire to people's hair and he'd just look at her in confusion because how in the world would he remember what happened when he was two and stuffing his face with whatever his little hands could get hold of?)


	4. Chapter 4

_Reborn (17 (57))_

He should have predicted this happening.

He was the world's greatest hitman and he really should have known better when the brunet mentioned that his uncle was coming to visit.

He'd been _right there_ when Tsuna somehow became friends with that creep Byakuran. Enma wasn't off the hook either.

But, realistically, who in Primo's name could predict this?

Slamming the door in the Vongola Famiglia's First generation Mist Guardian's face, Reborn turned to his roommate-slash-possible-romantic-interest.

"What the _fuck,_ Tsuna?"


	5. Chapter 5

_Tsuna (4)_

When Tsuna was about 4 years old, and on his way to visit his Uncle Kawahira, he met a weird baby with bandages covering his face.

(Nana did not know how her toddler of a son continued escaping the house every single time despite triple checking every entrance, every day. Kawahira didn't either and he thought his barrier would deter the boy from seeking him out, especially after Nana waved a pack of C4 in his face last time.

Tsuna had smiled innocently, finding absolutely nothing wrong with telling his mama about the 'nice Uncle Kawa who gave him candy and invited him to his house'.

The misunderstanding had been fixed up, but not before Kawahira had been mildly disturbed and he may or may not have blanked out a second recalling _his_ fellow element and that man's tendency to _blow shit up_.)

Either way, Tsuna met the baby, and the baby was trying to find someone.

Tsuna, who'd never been sealed thanks to his mama, and therefore had an intuition that already rivalled the Vongola Ninth's if not the mental capacity to use it, translated this into; the baby was trying to find his Uncle Kawahira.

But Tsuna wasn't allowed to bring strangers to his Uncle, so he first needed to become friends with the baby.

Tsuna had never had a friend before but he was pretty sure they played games with each other. "Let's play house, Tomodachi-chan*!"

Unfortunately, at four years of age, Tsuna had very little control over his pyro tendencies.

So although Bermuda was definitely going to snap out a firm 'no', he was deterred when Jaegar suddenly warped next to him, causing the child to yelp in surprise.

The two Vindice felt the same when _things_ around them -like the swing set, and the water fountain, and Jaegar's long hair- spontaneously combusted.

The child in front of them flushed, as if he'd just done something mortifyingly embarrassing. "Oops."

 **"My hair!"**

 **"...Why don't we 'play house'?"**

And if their playing somehow led to the Vindice inadvertently finding out how to cure the current Arcobaleno and wrangle the pacifiers from _that man's_ control, then all the more for them.

(Little Tsuna didn't understand why his spouse (Tomo-chan) and their pet dragon (Butler-san, because Jaegar acted just like a butler from that TV show his mother liked to watch) were staring at the fire he'd made as effects for Butler-san's role, but the black fire that was making his fire last much much longer than usual was really cool!)

* * *

Notes:

Tomodachi = Friend


	6. Chapter 6

_Tsuna (17 (18)), Reborn (16 (56))_

Reborn liked to tease Tsuna. And stalk him. And surprise him. And turn up at his lectures even though the man wasn't taking his classes and was actually his tutor in one of them... did he mention Reborn was stalking him?

But Tsuna was really flattered and just a little confused when Reborn burst from the gaudy red box in their living room dressed as cupid, scattering pink confetti everywhere.

Reborn just looked vaguely disappointed. "Where's your scream? Do you now how much effort I put into creeping you out, Tsuna?"

"You look adorable," Tsuna said without thinking. But really, Reborn donning wings with a heart painted on his bare chest, while still stubbornly wearing his fedora? Adorable.

Spanner and Shoichi, who'd come for dinner, exchanged an awkward glance. "T-that's quite a lot of effort you've put into surprising Tsuna, Reborn." Shoichi pushed up his glasses nervously.

"Of course," Reborn scoffed. "Too bad it didn't work, I'll have to try harder next time."

The two inventors shared another glance.

Tsuna tried his hardest to scowl, and _seethed_ as Reborn burst out laughing at his attempt.

"So cute." Reborn grinned, putting down his bow. (Shoichi was mildly disturbed to see it was a _real bow_.)

"I will burn your ridiculous sideburns off," Tsuna threatened.

"You won't, you think they're awesome."

Reborn grinned as Tsuna, unable to refute that fact, growled wordlessly and went for his sides. Too bad the brunet was even more ticklish than him.

Shoichi shook his head as the two fell into the confetti filled box and buried his head into his hands. "Why don't they _realise."_

Spanner patted the red-head's back comfortingly.

"We should start placing bets."

 _"Spanner!"_ Shoichi exclaimed, scandalised. He paused for a moment, then-

"...I bet they won't even realise when they start sharing a bed."


	7. Chapter 7

_A/N: Sorry if I don't respond to anything, I'm kinda inundated with work (and also severely sleep deprived), but I'll make any corrections that are pointed out. That said, thanks to everyone for reviewing, fav'íng and following this rather whimsical (as in, written on whim) story. :D_

* * *

 _Reborn (2, (42))_

Reborn still remembered the confusion that came with waking up one day without the heavy weight of a pacifier around his neck and Leon's large yellow eyes blinking down at him. The faintest scent of something vaguely sweet permeated his room, and the creases in his blankets indicated someone had been there and been pretty sloppy about it, but _he had not woken up_.

Reborn had never before wished that Leon could talk as hard as that day.

A few hours later, and all the Arcobaleno were gathered, missing their pacifiers and entirely confused. Even Lal, with only part of the curse, was missing hers.

A diagnostic test from Verde revealed the most crucial point; _They weren't stuck in a permanent limbo anymore_.

They had no idea what changed The Man in the Iron Hat's mind, or if was even him, but they could grow, and this time Reborn was sure, all of them, sans perhaps Aria, would appreciate this life far more than they had their previous.

They would never be grateful to the Man in the Iron Hat, but anyone else was fair game.

* * *

 _Tsuna (4)_

"Do you understand, Tsunayoshi?"

The child settled into the soft flooring of the little pod, surrounded by seven clear orbs, each containing a different coloured pacifier surrounded by black fire. He hugged the yellow one to his chest, recalling the baby with the awesome sideburns and, copying a show he'd seen on TV, saluted clumsily up at his Uncle Kawahira peering down at him from the opening. _"Roger!"_ He giggled, the English word rolling weirdly off his tongue.

Kawahira smiled indulgently, reaching in to ruffle his mop of fluff hair.

"Four, burning people, and already saving lives, this little lad's going to go far," cackled Talbot, rubbing the charred ends of his hair as Kawahira sealed the pod closed.

Tsuna wiggled his fingers at Bermuda, who huffed as he settled next to the pod but raised his hand in a regal wave regardless, since the child wouldn't hear him anyway. He couldn't help a jab at the most hated existence in his life though. **"After this, the pacifiers will be ours."**

"Tsunayoshi is the one providing the Flames."

 **"The Vindice repays their debts."**

"What a coincidence." Kawahira smiled enigmatically, eyes hidden by the reflection of the orange glow from the pod. "So do I."

Talbot resisted the urge to roll his eyes -which wasn't too hard considering that he didn't have eyes anymore- but the sentiment was there. "As long as I'm not dealing with the boy's mother."

Bermuda claimed, **"I have duties here."** Just a tad too fast to be called calm.

Kawahira said nothing, but he did seem a tad reluctant in using his mist Flames as he warped back to Namimori.

Talbot chortled, sparing an unseeing glance at the slumbering child inside his contraption.

Four years old, had two ancient beings twisted around his little fingers, and a mother that kept them in line.

Perhaps he could live another few decades, just to see how this would pan out.


	8. Chapter 8

_Tsuna (4)_

As Tsuna incubated the pacifiers, he dreamed.

He saw someone who looked miraculously like an older him, windswept wild hair, and with so much inner fire his eyes _glowed._

He saw an angry man who could shoot fire beams from his guns, blue fire that paralysed, indigo fire that created things from thin air, the babies he briefly met when he went to fetch the pacifiers, and lots and lots of colourful people and flames.

He cried as people perished and watched in wonder as twins were born.

He saw miraculous worlds full of magic, and others filled with winged people, and still others where no one looked human.

But they couldn't see Tsuna.

But he wasn't too lonely. The animals could still see him; the Arcobaleno's, as they were usually called across several worlds, animal partners were his favourites. Oodako gave the biggest best hugs (as long as you didn't mind the damp), Falco always showed him interesting ways to fly (and that was a bonus too, Tsuna could now fly!), Keiman gave him rides while Leon commandeered the spot on Tsuna's head and Fantasma lived in his shirt, and Tsuna loved stuffing his face with grapes with Cosmo in that one world where the Arcobaleno were big and there was a lady with a puffy hat.

He could also seek out the Uncle Kawahiras for some ramen (he couldn't really interact with any of the worlds when other people were there, but when Tsuna was alone he _could_ nudge a few things, like sneaking the Super Instant Magic Ramen from one of the Kawahira's stores for his own Uncle).

* * *

While Tsuna was bouncing around space and time, much like a rainbow that appeared sporadically, Kawahira and the Vindice came to a similar conclusion (neither knew this, or Bermuda would have committed seppuku, right after grinding Kawahira to his bones).

As far as they knew, Tsuna was a legitimate heir to the Vongola throne.

Kawahira was aware that the Vongola Nono's sons were not going to last beyond Tsuna's childhood and he well understood the despicable side of humanity and the mafia were _filthy._ If he kept the sons from dying, Tsuna could get a proper life.

Vindice, after some investigation, came upon one Daemon Spade infiltrating Enrico Vongola's inner circle. As a favour to the one that granted their greatest desire, they decided to apprehend the man and leave him to Tsuna's tender mercies.

* * *

Tsuna slept on.


	9. Chapter 9

_Tsuna (4 (5))_

Daemon was not pleased to be in the custody of a child. Even less so when said child was Giotto's descendant.

However, Tsuna was stubborn and wanted the sad blueberry pie to be his friend. (He got some weird and rather horrified looks from Uncle Kawahira and Daemon when he said this aloud. The looks did not change when Tsuna attempted to describe just how sad the blueberry pie that he made with his mama had been because they forgot the sugar.)

(Sugar makes things happy.

You should never forget sugar.)

But eventually Daemon caved and vowed to beat clumsiness out of the boy because there was only so much hair he had left to burn. _He wasn't even a living entity so how was he even getting set on fire?_

The first day little Tsuna managed to set fire to his father's picture on purpose, Daemon was so proud he ruffled the boy's hair. The beaming smile he received did weird things to the ghost's decrepit heart and he felt almost happy (it was either that or the child's smile had exorcising properties), and this was apparently enough to see his beloved Elena and finally learn that he'd been going about the whole Vongola problem the wrong way.

Vongola could take care of themselves. Giotto's descendant, however, was never going to even remotely end up like Iemitsu if Daemon had anything to say about it.

(Daemon's position during his last stint before he was captured by Vindice put him in unfortunate close proximity to the exuberant blond man.)

Luckily, Tsuna's other uncle agreed, for all that he wasn't human and probably had the emotional capacity of a stoned lemming (Daemon really didn't have much ground to throw stones).

Little Tsuna blinked at the scheming smirks his uncles shared.

He promptly tripped over his laces and set Daemon's hair on fire. Again.


	10. Chapter 10

_A/N: I'm a little (a lot) disorganised so updates are really random, I might post two or more chapters at a time (like I did last update) so keep an eye out. (sorry)_

 _I'm hope those who are reading this rather segregated story are somewhat entertained at least. 8)_

* * *

 _Reborn (16 (56)), Tsuna (17 (18))_

Reborn stopped at his assigned room. He'd already done a preliminary check on his roommate's background; perfectly ordinary kid from a small town in Japan, mother, step father and step sibling, graduated with average marks and high proficiency in a number of languages.

He was about to unlock the door when it slammed oped, and someone ran into him.

The only thing Reborn could see was fluffy hair as his hand automatically came around to steady the both of them.

But really, the hitman's attention was more on the snarling, razor toothed, and _holy fuck_ but how did a _lion_ get into an apartment?!

It took barely a second for Reborn to have Leon in gun form.

It took two seconds for the person mushed against Reborn's chest to yell, "NO!"

The sound of his gun going off would have been loud if not for the fact that Reborn's beloved hat was suddenly on fire.

The other person yelped, "crap!" While the lion cowered behind them.

And Reborn just stood there a second, absolutely flabbergasted at the heat on his head.


	11. Chapter 11

_Tsuna (17 (18)), Reborn (16 (56))_

Hana was going to kill him, if this hitman didn't first.

He could already hear the lecture about how setting things on fire wasn't _normal_ and his family and friends were not a valid metre to measure to so Tsuna had no right to use them as an excuse.

(Mostly because Tsuna already received that particular lecture before leaving for foreign soil bereft of his usual company.)

So people reacted a bit extremely when they saw Natsu, that was no reason to _shoot_ him, leading to Tsuna having to melt the bullets before they reached his beloved companion and accidentally set the perpetrator on fire too (bad habits were hard to be rid of when half his friends were goading them on).

Why the _hell_ was this hitman here anyway?

"I'm your roommate," said Reborn, partially annoyed that he'd revealed his hand so early, partially intrigued by this pyro's open expressions. He still mourned his poor hat though.

"...roommate?!"


	12. Chapter 12

_Tsuna (4 (5))_

Tsuna had a vivid imagination. Jumping through a number of worlds just catalysed this.

Tsuna also had a pair of exceedingly powerful illusionists at his disposal.

Needless to say, his childhood was filled with epic adventures, and scenery so beautiful they could render even an excitable fire-setting-child speechless.

(Nana had a _talk_ with Daemon about being a child-friendly influence.

It may or may not have involved a can of hairspray and nail-polish.

Daemon wondered why someone hadn't banned the woman from purchasing flammable substances. (Somewhere, one little Kyoya watched his father sneeze. The store manager he was talking to almost wet his pants in fear.)

Either way, little Tsuna didn't get to poke any more zombies struggling to crawl out of the earth.)


	13. Chapter 13

_Reborn (16, (56))_

He was either getting way too old for his teenage appearance, or killing people was actually getting boring.

Being the best of the best came with a number of caveats, specifically, if you stayed the greatest in your field of work for long enough, you'll end up knowing every trick in the book and then some, and Reborn has been in his position for far longer than anyone else.

As much as he preened at the fact he could terrify the tar out of hardened mafioso with mere mention of his name, Reborn was, in fact, finding hits needlessly monotonous.

Finishing off the corrupt politician he'd already shot in the hand after the idiot tried to go for his gun, and completely ignoring the frozen woman that had been with the man, the hitman stalked off, mind made up.

Since puberty was mostly over and done with (thank fucking _god,_ going through that once was enough, twice was a rather painful form of torture) he could pass off as a few years older and go back to that old college degree he did a couple decades back just to prove that being stuck as an infant was _not_ going to stop him from doing what he wanted.

Maybe he could teach too, that was always _fun._

(A few months later and rumours of the demon-tutor of MATH4009 and PSYC3027 would spread across campus, inciting fear and terror.)

Reborn chuckled to himself, peripherally aware of the woman's gaze on his back.

* * *

 _Tsuna (17 (18))_

Tsuna resisted the urge to burn the hitman bald. Regardless of awesome sideburns.

Not only had the man stolen their pay to a comfortable place over in England, he had rendered this need to dress as a girl absolutely pointless.

He glared down at the silky fabric. Spotting the blood seeping into the hems, he silently despaired.

Haru was going to kill him for getting blood on this dress, if Hana didn't first for losing their target.


	14. Chapter 14

_Tsuna (4 (5))_

Tsuna's first friend that wasn't ancient and actually human, was Yamamoto Takeshi.

They met at Takeshi's mother's funeral.

Takeshi was mourning, incredibly sad, and lonely despite his father's best efforts to be there for him.

Yamamoto Tsuyoshi was a brilliant man, even with his prior occupation. But he was still human and also weighed down by his own grief.

And Takeshi, standing there and clutching his stick of incense, just didn't understand.

Why did everyone around him say 'you should smile, that's what your mother would want!' when, really, he just wanted to do the exact opposite?

She wasn't around to scold him for sneaking out with her favourite baseball and subsequently break their neighbour's window, immediately take him out to play and eat ice-cream and whisper in his ear, bright and cheerful, about how old crotchety Yamanaka needed more _fun_ in his life. She wasn't around to help him steal slices of dad's sushi behind his back and giggle as his dad made a show of searching for them, hiding in their pillow fortress.

What was the point of smiling when the source was gone?

In one world, Takeshi would come to the conclusion that it was so no one needed to worry about him and eventually learn to bury his grief under a wide grin, developing a festering habit as his motto became 'grin and bear it' until the strain of social cues and baseball became too much.

In this world, a wondering wizard provided him with an answer.

"There's lots of types of smiles, and I think you just lost one of them; the one you share with your mama."

Takeshi blinked at the kid in a dark navy with a star pattern robe with wide sleeves, a gnarled old staff, pointy hat and long fake beard that trailed almost to his feet. He looked almost ridiculous, if it weren't for the bright amber eyes staring right into his. "You still have other smiles though, and you'll make new ones, when you encounter other things to be happy about."

"What if I don't?"

The wizard tilted his head, his pointy hat slid over an eye in the process. "I'll make them." A wide smile could be seen behind the fake beard. "Tsuna will make things for you to be happy about!"

Takeshi felt his eyes sting and he quickly scrubbed an arm over them even as a small hand came to rest firmly on his shoulder.

Then, soft as the slightest breeze, "...I miss her."

Tsuyoshi wondered where the little wizard came from, but as his son moved to clutch the other child in a desperate hug, shoulders shuddering in a way Tsuyoshi had been trying to coax out of him since his wife's death, he couldn't help but feel a little magic was at work here.

Tsuna hugged his new friend just as fiercely and smiled as he pressed a finger against the tip of Takeshi's incense, releasing a steady stream of smokey wisteria scent.


	15. Chapter 15

_Tsuna (4 (5))_

Kurokawa Hana and Sasagawa Kyoko were walking down the hall when they overheard that gloomy Yamamoto kid and the new kid talking. (New, because he was the last to enter the class, two months later than everyone else.)

"-what did Uncle Daemon end up getting you for your birthday?"

Hana rolled her eyes, of course the kids would be talking about the 'epic' presents they got for their birthdays-

"... A unicorn."

What.

"What?"

Now that they were further down the hall, the girls could see the two boys sharing lunch in the tree outside. (Kanda-sensei was definitely going to yell at them for climbing up again.) The new kid -Tsuna, his name is Tsuna- had a long suffering expression on his young face.

"I love Pika-chan very much, but I don't want to make mama have to clean up after her. She just sheds so much."

"Like... Fur?" Yamamoto asked at the same time Kyoko piped up, "that sounds like a really cute toy, Tsuna-kun!" Before Hana could stop her from joining the nonsense conversation.

The little brunet looked appropriately scandalised. "She's not a toy! She's really nice and white and fluffy and sheds lots of rainbow glitter!"

"Unicorns don't exist," Hana deadpanned, unable to help herself.

Tsuna gasped, and he looked like the type of kid mothers would squee over, what with the fluffy hair and expressive eyes. "How could you say that? What about youkai and pokemon?"

Hana's brow twitched. "Those don't exist either."

She definitely didn't feel bad when those large amber eyes teared up, really.

* * *

Daemon was suffering from a mild bout of insanity, clearly.

So he had a bit of fun with Tsuna's TV shows and books, it was always amusing to watch the child get so excited the grass around his feet started catching fire.

But that didn't mean he had to feel guilty when Tsuna ran home one day, turned to his unicorn with eyes aglow with Sky Flames, screamed, "Nooo!" dramatically and proceeded to cuddle his illusionary unicorn while sobbing, "I wish you were real!"

Pika nuzzled him, and got more sparkly glitter on his cheeks.

After that, two girls and Takeshi ran in, huffing and puffing, and proceeded to watch before turning vaguely accusing eyes on him -the only adult in the house as Nana had gone shopping.

It wasn't like _he_ was the one who told the boy that mythical creatures didn't exist.

It wasn't like he got another pet for the child because he was feeling _guilty_ either. The circus just happened to be there, fortunately. (The circus would disagree, if they were in any state of mind to).

The moment Daemon stepped into the house with the ball of fur in hand, Tsuna's eyes lit up.

"You're my favouritest person ever!" Declared the child as he hugged one of Daemon's legs, leaving the ghost to feel that fluttery sensation in the pit of his stomach as Tsuna turned to the furball. "And I'm going to call you Natsu," ha said, immediately in love with the lion cub.

Natsu gao'd and licked his nose and Daemon felt immensely proud for some reason.


	16. Chapter 16

_Reborn (16 (56))_

By the time a week or so had passed, the two had set up a sort of routine. Tsuna prepared breakfast while Reborn broke out his coffee and Tsuna's flavoured water ( _Tea, it's called tea, Reborn!_ ). They'd make small talk before heading to class (if they had one), lunch was generally packed by Tsuna or they bought it on campus, and dinner was normally prepared by the both of them.

(Tsuna started out making them both food without Reborn ever requesting it. Reborn joined when he realised how fun it was talking about various foods while testing recipes together. Reborn _could_ cook but never exhibited a preference for it, he also liked his food to be at a certain standard. Somehow, Tsuna managed to both produce quality and make the entire process _fun_.)

One night, Tsuna was meeting up with a group for an assignment, leaving Reborn to have dinner alone. Tsuna's laptop happened to be flashing tantalising from his empty room, and let it not be said that Reborn wasn't a curious man.

Two screens opened up with a simultaneous "Tsuna/Tsuna-kun!" And that was how Reborn met one cheerful Sasagawa Kyoko and a friendly Yamamoto Takeshi.

"Did you know Tsuna-kun believed in faires and unicorns until he entered school?" Kyoko grinned, innocent and coy all at once. Reborn was ever so thankful he was fluent in Japanese for all that Tsuna barely displayed an accent when he was speaking. "He was so cute back then!"

"Still cute now," Reborn said with a chuckle, recalling how the brunet made the most adorable sound when Reborn jumped out at him one night as he went to get a glass of water. The fridge ended up in flames and Reborn had to chip in for a new batch of groceries but it was so worth it. (Except, perhaps, for the fact that another hat was sacrificed. Burned into so many ashes.)

Kyoko'd eyes widened as she let out a suspicious, "oh?" Which was easily covered up as Takeshi laughed and interjected, "Tsuna thinks you're awesome."

Reborn raised one brow dramatically. "Did he now?" He didn't detect any obvious attraction from the brunet, not like the way some of the students swooned when they saw him (and how proud was he of _that_ , 35 years spent too young to receive anything but endearing coos was _more_ than too much).

Takeshi hmmed and said, "he was talking about your sideburns actually-"

"But I'm sure he finds you very _very_ handsome Reborn!" Kyoko piped in with a bright smile.

Reborn blinked, slowly, getting some really weird vibes from the woman when Tsuna finally turned up.

"Reborn, did you have dinner yet? I- Did you just hack my computer?!"

The hitman plastered a perfectly innocent expression on his face. "No."

Tsuna's brow twitched as Kyoko and Takeshi's laughter rung out of his speakers.


	17. Chapter 17

Summary: How Nana got her hands on explosives. Ft. Kyoya's dad, little Kyoya, and a dragon.

* * *

 _Tsuna (4)_

"Kou-kun!"

Little Kyoya, sitting on his father's desk and quietly watching his father work looked up as a bright, cheerful creature _pranced_ into his father's office with nary a knock.

His father was abnormally stiff as he raised his head and Kyoya expected some sharp reprimand that would put this herbivore in her place.

That did not occur.

"Kasai."

"How many times have I told you to call me Nana?"

"I hear you accessed the restricted area for confiscated receptacles."

A light laugh. "I returned it, didn't I?"

"My staff's function was compromised when they discovered we were missing one of our explosives."

"Don't be silly, I _told_ them I was going to borrow something."

"I do not think anyone heard over the _sprinkler system_ -"

Kyoya really would have paid more attention but a child in a green dinosaur costume with orange spikes that went from the top of his hood to the tip of his tail had manoeuvred his way up onto his father's table. The black haired child blinked down when a cookie was offered in a stegosaurus shape then back up to where the child with amber eyes was chewing on a T-rex.

A single sentence slipped from the dark haired child, full of accusation:

"Cannibalism."

This led to Tsuna dropping the cookie, absolutely horrified because he hadn't realised what eating dino cookies as a dinosaur meant. This also meant, as a young and impressionable pyro, that the nearby water dispenser caught fire.

"Oh no," Hibari Kouga muttered, almost unable to believe his eyes. Recalling incidents such as the school kitchen explosion, the mysterious combusting tree and the now non-existent warehouse in the warehouse district, which were all somehow related to Nana Kasai who was his senpai in both middle and high school, his typical stoic features actually crumpled for a brief second.

"Oh yes," said one Nana, immensely proud her son had enough mind to set fire to a water dispenser rather than Kou's nice, dry, and very flammable paperwork.

"Dragon." Stated one Kyoya, trying to recall which dinosaur creature set things on fire.

Tsuna was too busy hugging his beloved cookie, blabbering apologies to notice the despairing man, his overly proud mama, and the other child, tugging on his spikes and attempting to see if anything else would spontaneously combust.

* * *

That night, after Nana had coaxed a promise from Kouga to inform his wife that she should visit the Kasai home when she was back, the man gathered his son and the Kusakabe child, had them sitting in front of him in seiza, and stared them both in the eye. "You should never approach the Kasai flippantly," he said gravely. "The ones that exhibit their penchant for fire have always been an exception from the social hierarchy."

Kyoya nodded and said, "Herbivore dragon."

Kouga tried for a smile at his son but it probably came out as a grimace. His wife always had a penchant for animals and taking their rather intelligent, if somewhat reserved, son to the zoo for the entire 'animal kingdom' week resulted in some very odd word choices (at least he was upgrading from one word sentences).

He hoped the young Tsunayoshi Kasai setting fire to his son's hair hadn't made a lasting impression either, and that Tsunayoshi recovered quickly from his son's subsequent rough treatment (he now needed a new desk after half of it burnt into a black crisp, and maybe he was thankful to Nana for keeping his paperwork safe but there was no way he would show any such emotion around the woman for all the migraines she caused).

The _last_ thing he needed was a stubborn Hibari inciting a Kasai's (literally) burning rage or fear or excitement or, really, any emotional output.

* * *

Unfortunately, his wife had other ideas, and Tsuna and Kyoya was exposed to each other on a monthly basis for play dates that, more often than not, ended up with someone's hair on fire and a number of bruises. ( _That child is too much like Alaude!_ Daemon cursed and consoled himself with, _at least Tsuna didn't end up like Giotto._ )

Middle school Tsuna often wondered why people shied away when he told them Kyoya Hibari was a childhood friend. It wasn't like he was excluded from all beatings.

Middle school Kyoya learnt long ago that it was futile to stop the chaos surrounding the brunet lest he end up like his father. Now, if only the dragon and his clutch would _stop_ breaking the rules.

"Kyo-san, the pool is on fire." Kusakabe reported stoically.

The newest member of the Disciplinary Committee, who'd been reorganising the filing in Kyoya's office, did a spit-take. "How the fuck does a _pool_ catch _fire?!"_

The satisfying sound of his tonfa against the herbivore's head was the only consolation to Kyoya's growing migrane.

* * *

Guess who~

(Man, I never meant for a whole chapter on Kyoya, he just shoved his way in.

I never meant for an entire chapter on Takeshi either, now that I think of it.)

Thanks, as always, for reading!


	18. Chapter 18

_A/N: I don't think the review function is working through ffn? I still receive the emails though so in response to Armed Truth_ _about incorporating a TYL arc: Sorry, but I think I've already stuck Byakuran in (somewhere?) for the 17yr old Tsuna and Reborn to deal with (also it's not feasible because Lambo isn't around when Tsuna's 14). Thanks for your amusement either way!_

 _I should warn to the Hibari fans that Kyoya probably won't appear very often (depends on how many kid!Tsuna chapters there are) but he's really just not that involved in the plotline (is what I say but this is a WIP so anything goes...) but I'm happy to have garnered some laughs with chibi!Kyoya and pyro!Tsuna. (Also happy to see no one seemed too put off by Hibari's parents, I'm not very good at making OCs.)  
_

 _Anyway, enjoy the next installment of Incendiary! (Which, really, should have appeared long ago if this fic had an order, but it doesn't so, yay for non-linear plotlines.)_

* * *

 _Tsuna (3)_

When Tsuna was three, his house burned down.

There were two visitors that day, a loud blond man, and a kind elderly man.

Tsuna was playing in the garden with his neighbour's chihuahua, a skinny creature that looked more like that creepy golem Tsuna saw on TV a week back than a dog. Tsuna was, naturally, terrified, but for some reason he felt using his fire was a horrible idea so he was trying very _very_ hard not to. This lead to different fire coming out. (Different, because instead of a heat that emerged when Tsuna was emotional or willing it, and appearing on whatever Tsuna directed the feeling at, this one simmered from a place deep inside him and emitted from his body like a soft glowing second skin.)

Then, the old man was in front of him, a single finger lit with that same inner fire and Tsuna was crying for a different reason entirely as the same thing inside screamed _'get away!_ ' so he-

For Nana's part, she'd rushed out when she heard her baby son's cries, to the sight of Timoteo exclaiming as fire caught his hand, burning and blistering through layers of skin and muscle.

Trusting a three year old wasn't what most people would have done, but Nana _knew_ her son, knew her innocent baby boy had never burnt anyone beyond their hair and trusted he wouldn't do so unless he had a good reason.

She thought she was content to play the role of a loving housewife; after all her son filled her the heart where Iemitsu's absences left cracks, but when she saw her husband's boss; visiting, and appearing so kind, much like her own grandfather had been, reaching out to do _something_ to her three year old son-

The odd orange fire Nana didn't recognise as _flame_ she'd glimpsed on Timoteo's finger before it caught on actual fire, and Iemitsu who was just _standing_ there doing nothing, and was now paying more attention to his boss than her darling son, who was sobbing terrified tears as he scrambled back and into her arms as she caught him, made something _snap_ inside and-

-Nana may not have ever lit something out of her line of sight, nor would she ever have as much an affinity for flame as her child, but the kitchen was her domain and she knew exactly where everything was located, including the gas source. All it took was one little spark-

 _BOOM_

-The house she and Iemitsu chose during their honeymoon went up in a blazing glory.

Nana nabbed her son while the two men were entirely distracted by the flying shrapnel and gouts of fire. She quashed her feelings of guilt as she heard Iemitsu call frantically for her; the vision of Iemitsu standing there, looking almost _approving_ of what that old man, Timoteo, was going to do to her son made her squeeze her Tsuna that much closer.

"Mama?"

Nana looked down at her little boy as flames illuminated his large eyes a brilliant orange. She made herself smile, and it probably appeared a little wry as she said, "apparently, Mama loves you the most."

Tsuna's brow crinkled as he reached up to touch his mother's wet cheeks. The curl of warmth inside his chest wanted- no, _needed_ his Mama to be happy. "Tsuna loves Mama more," he said, with all the seriousness a three year old could muster.

That got him a laugh, and Nana felt her heart swell even as she ran through her burning home and away from her husband and his boss. At least fire would never hurt her or her precious little boy.

* * *

Nana offered no answers to her husband as she mailed the mostly signed divorce papers to him.

Iemitsu asked no questions, assuming that it had been an assassination attempt and that Tsuna's Flames were just a bit more violent -which was bad for a child so young, what if he burned someone by accident?- and that it was probably for the best as he'd nearly _lost_ his beloved Nana and his son in that explosion.

He could always send someone else to seal Tsuna's flames, after all. Better a stranger than him to be at the end of such a tearful, horrified gaze.

(Iemitsu Sawada was a man of good intentions, and horrendously bad decisions.

And if he never noticed how robotic the one sent with the seal and reported back success sounded, then it was his -and subsequently Vongola's- loss.)

* * *

Kawahira, wondering at the defensiveness he was feeling over the child but knowing better than to reject it, chuckled to himself as he helped Nana settle into a new place. Tsuna, bouncing on his knee, giggled, inexorably happy that his other favorite person was happy.


	19. Chapter 19

_A few months after starting University/College_

"I don't really like this one," said Tsuna as he placed the card into one of the piles on the table.

"This one looks alright," said Reborn, pickling up another card. "It'll go nice with the stainless steel in the kitchen don't you think?"

Tsuna bent closer to look and Enma almost blurted _"why don't you just kiss"_ what with the way the two were pretty much joined from shoulder to hip, faces so close together that all it would take was a clumsy Shōichi or a purposeful Byakuran for them to mush heads, or lips, or maybe just finally fall into blissful sin so that the rest of them wouldn't have to watch any longer. It was actually getting physically painful.

Hell, Enma even witnessed saw their tutor in macroeconomics make a jibe when he told _"everyone get into groups of three for this task, 'cept for you two, anyone working with you guys will feel awkward as shit"_ (Enma questioned how no one seemed to notice Reborn wasn't supposed to be in their classes for the last six weeks.) He was also correct because Enma was slowly dying inside watching the two talk about -he glanced over the cards- _kitchen tiles_ , for the last twenty minutes.

Unfortunately, he had about five thousand euros riding on Tsuna and Reborn accidentally getting married before finally realising their very obvious attraction to each other. He had another thousand on the two kissing and _still_ not realising.

"Let's move to the curtains next," said Tsuna, having somehow decided on a colour while Enma spaced out, contemplating his friend and stern roommate's _'non-existent relationship'_.

"You mean our tank-proof automatic blinds?"

Tsuna rolled his eyes fondly and patted Reborn's arm. "Of course."

Enma groaned silently and vowed never to have lunch with the just the three of them ever again.

* * *

A/N: Nothing burning here, but some R27 fluff and Enma suffering in silent agony! Next couple of drabbles are probably going to only feature adult-verse.


	20. Chapter 20

_Tsuna (17(18)), a few days after meeting Reborn_

Tsuna dropped into a chair and dropped his head against the surface of the table.

Shōichi patted his friend's back, and made vaguely comforting noises.

Spanner glanced up from his laptop, one brow raised. "It's only the first day."

"I got a roommate," said Tsuna to table.

"Serves you right! I _wish_ I had a room to myself." Shōichi exclaimed.

"Ouch, Shō. That hurt, truly," deadpanned the blond.

"I accidentally set his fedora on fire," Tsuna continued. At least the table listened.

"Spanner, that last mosca you built is three metres tall and weighs over 200kg."

"His name's Reborn. He's somehow in all my classes and also my _tutor_ in Psychology. I'm pretty sure he's younger than me!" Actually, mentally prodding at his intuition got him a really confusing response when it came to his hitman roommate, like it couldn't decide if Reborn was young or an old man.

"So?" Spanner stared at the brunet, ignoring Shōichi's ranting.

Tsuna lifted his arm to shake a fist in the vague direction of his two friends. The two got conscripted into doctorates within their first day of university because they were absolute _nerds._

"He's a sadist," Tsuna continued to list. "He pointed a gun at me. He called me clumsy. He's got a devastating smirk. He looks adorable in his pyjamas. _I don't understand._ "

Spanner and Shōichi shared a look, before the red-head paused, then, "did you just say you set this guy's hat on _fire?"_

Tsuna whined and banged his head against the table.

"Tsuna, we talked about this!"

"Why aren't you asking about the fact that he has a gun?" Tsuna moaned plaintively.

"Because we can _make_ guns-" Shōichi started before his brilliant mind computed that fact that this guy wasn't a part of their group and therefore shouldn't _have_ a firearm in the middle of a school in the UK. "Why does he have a gun?!"

"Because I'm awesome." The two inventors jumped as a tall dark haired man appeared and leaned his black sweater clad upper body over Tsuna's bent back, one elbow jabbing into a shoulder as he smirked. "Chaos, I'm Reborn," he greeted the two inventors as Tsuna made more dead animal noises. "I just happened to overhear that you two can make guns." The grin that stretched his features was sadistic to a fault, three passing witnesses actually _fainted._ "I like guns."

 _Oh god, not another weirdo,_ was the only thought Shoichi managed.

* * *

The next few rants about Reborn were mostly along the lines of the man actually _attempting_ to startle the brunet for some maddening reason, Reborn's weird obsession with his fedora's.

-"He has an altar, gives an eulogy for every single hat I burn, and makes me buy flowers for them every other week."-

The man's attempts on Byakuran, their neighbour's, life and vice versa (or so Shoichi translated).

-"I actually think they're playing with each other, or something. There was a marshmallow cake and paint-guns involved, oh, and one time Byakuran gave him a doll! It had a lot of nails in it, but I took them out for Reborn. It looks fun whatever they're doing."-

And it took an embarrassing long time for the red-head to realise, but Tsuna wa _s head-over-heels_ for this hitman.

 _Spanner_ noticed before him! ("Well, he's pretty much the only thing he constantly talks about. And Reborn really likes to ask about Tsuna when I meet him to test some of the inventions.")

The only conclusion Shoichi could come to, was that he was glad that none of the others were here.

(That did not mean, however, that they didn't know. There were some things Shoichi just could not avoid, Nana-san was one of them, a Hana intent on grilling him was another.)


	21. Chapter 21

_Tsuna (17 (18)), Reborn (16 (56))_ _About two month's since becoming roommates._

Tsuna was moving out.

The many real estate documents with properties circled out and Tsuna's browsing history all pointed to this fact. Never mind Tsuna was aiming for a rather large place in, or close to, public areas, the fact that Tsuna was trying to find a new place was evident.

Reborn didn't exactly understand the uneasy feeling he was getting, maybe it was because he honestly _enjoyed_ the fire-setter's company, and Leon's favourite daytime perch aside from his fedora was actually in Natsu's mane. (The little chameleon rolled his large yellow eyes and wondered at his partner's propensity to annoy the human with soft hair, which often resulted in his comfy spot ending up in flames.)

Maybe he'd teased Tsuna a little too much? ...Nah, Tsuna was hardier than that. Brushing off the weird feeling, Reborn decided to just ask.

"Are you moving out?" Was the question that met Tsuna the moment he came home.

Tsuna blinked a few times, computing the question then frowned in confusion. "No?"

Reborn wordlessly pointed to the piles of magazines and printed documents he'd gathered from Tsuna's room.

Tsuna was half tempted to say _something_ about Reborn's clear lack of understanding the concept of _personal space_ but he didn't need his intuition to know a lost cause when he saw one. "That's for my friends," he said, then lit up as an idea came to mind. "Would you like to help?"

Reborn, feeling an unreasonable amount of relief he didn't quite understand, didn't really question it as he agreed.

"Sure."

* * *

Tsuna handed a sheet to Reborn. It was apparently a list made by multiple people and a number of different coloured pens.

- _Bakery (You can help me, Tsuna-kun!)_

 _-Boutique (Haru will make more amazing costumes!)_

- _Restaurant (Sushi!) (Italian is a must, Tsunayoshi) (Ramen.) (Yum cha!)_

 _-Art store (you know our sister makes beautiful artworks, Tsunayoshi)_

 _-Bar (I can play my music...)_

 _-Consultation company (You know this makes more sense, Kasai!)_

 _-Library/Book store (Please, Tsuna-nii?)_

 _-Tutoring institute/School (An EXTREME one!)_

 _-Gym (We can all exercise to the EXTREME!)_

 _-Garden shop (...thanks)_

 _-Pet store (We'll be the best one, byon!)_

 _-Haunted house (I think this will work well, with our talents.)_

 _-Robot cafe (I hear there's one in Japan, we could totally do one)_

Reborn felt a tick developing on his brow. "I understand your friends having dependency issues and wanting to set up a business so that you can work together, but surely they could have come to a single decision instead of handing you _this_?" He waved the sheet in Tsuna's face.

The brunet sighed. "Reborn, if you, say, wanted to set up a cafe what with your coffee obsession and everything, would you let another person's opinion convince you to create a different store instead?"

"Of course not," Reborn scoffed, paused, and conceded. "Point taken." He picked Leon off Tsuna's head as he glanced over the sheet again. "I _do_ want a cafe, and not a robot one, by the way."

Tsuna twitched.

* * *

A/N: Tsuna has many siblings, this will be established, as will the reason Reborn didn't know. (Well it's in my head, I've just got to remember to type it down...) No one who wrote in that list is an OC.

Another thing, I will be slowing down because I very much desperately need to focus on my major project (like, I have less than 20 days to produce a publishable 80 page report, _help.)_

Btw, your reveiws make me so happy. Much fun to read. Thank you!


	22. Chapter 22

**A/N:**...hello? Been absolutely months since i last updated (but it wasn't a year, at least?). I finished my thesis and have been to several countries since (of course Japan, and also Italy. Much regrets about not setting this story in Italy now seeing as i've never been to the UK.)

This story is still a WIP. I have no idea where I'm going with it still? But I'll post a chappie every day or so till i run out again.

(Also I'm thinking of changing the title.)

Much thanks to everyone whose stuck to this silly story of mine. I'm always happy to see others enjoying it.

* * *

Byakuran was, well, their weird neighbour that Tsuna inexplicably got along with, and Reborn hated with the burning passion of a thousand suns, or something like that. Tsuna didn't exactly get it beyond the fact that their first meeting was rift with flying bullets and marshmallows and Tsuna had been woken at a godawful time in the morning

For Reborn, it wasn't so much that the fickle Gesso heir, known because they had an alliance with the Gilgio Nero (Luce's famiglia), was posing as a normal student (it was Reborn's idea _first_ dammit) but that Byakuran was utterly creepy but Tsuna never seemed to _notice_.

Oh, Tsuna noticed already but he had plenty of experience with seemingly creepy people and Byakuran kind of reminded him of Mukuro, except with more cheer and marshmallows.

(Frankly, the only reason Tsuna could even tell was thanks to Hana and even his mother pulling him aside at a few points during his childhood to tell him that yes Kawahira was a perfectly nice person but in normal society, inducing sleep through illusions and tucking him into his own bed was normally considered creepy.)

"Tsuna-yo-shi~" _bang!_ "So cruel!" _bang!_ "Tsuna-" _bang!_ "-shi" _bang!_ "Would hate-" _bang!_ "-All-" _bang!_ "-Noise!"

"Then stop throwing fucking marshmallows onto our balcony."

"Hmm... No." _Bang! Bang! Bang!_

Tsuna stuck his head out of the sliding door, watched Reborn dressed in one of his oversized hoodies and a pair of black jeans fire at the marshmallows pelting their balcony courtesy of Byakuran, and sighed in exasperation. "Genkishi," he said over the noise of gunshots and marshmallows being squelched against Byakuran's balcony due to Reborn's exceedingly accurate shots. "If you stop Byakuran, I'll stop Reborn."

The dark haired man, who'd stuck his head out when he somehow heard Tsuna over the cacophony, gave a curt nod and disappeared. Tsuna didn't even have the heart to be surprised when he emerged again, brandishing two swords. He was, however, startled when the man _sliced_ through the entire floor joining the balcony to the apartment.

Byrakuran's startled yelp as the floor collapsed under him was nothing compared to Reborn and Tsuna's stares as Genkishi resheathed his swords, nodded once again to Tsuna, and shut the sliding door behind him as he disappeared into his and Byakuran's shared apartment, now lacking one balcony.

"What did you do to get _him_ on your side?" Reborn accused, dark eyes narrowed.

Tsuna opened his mouth to deny any involvement, frowned, then, "I gave him cookies? Once? I mean, that can't be it, can it?" He turned desperate, pleading, eyes on the hitman. " _Can_ it?"

Crickets chirped and as Tsuna glanced over the railing when he heard Byakuran a floor below, flippantly apologising about the sudden appearance of an extra balcony and offering marshmallows as reimbursement, Reborn took the opportunity to make himself scarce. He may marvel at the lengths people fell when delicious food was involved, but he would _not_ be the one to answer Tsuna's question.


	23. Chapter 23

_**A/N:**_ Double post today. Please check previous chapter in case you didn't read it. Xx

edited to add in the bit at the end, i knew i forgot something oops

* * *

The most troublesome decision of Tsuna's life occurred when he just started middle school.

On their first day, Kyoko came up to them and announced, "let's make a club!"

Hana had raised her head from her textbook (it was the first day!) and said, "I don't mind as long as we're getting something in return."

Takeshi just nodded along even though Tsuna was sure he had intended to join the baseball club.

Shōichi shrugged and shuffled closer to Tsuna in a bid for solidarity, a little nervous at being in the classroom. (He wasn't supposed to be in school with them, being a certified genius and all. Tsuna wondered where his Uncle got the uniform.)

And Tsuna just nodded slowly, having had no intention to join clubs in the first place.

So with neither fanfare nor dramatics, the 'we'll-take-requests-in-exchange-for-payment' club was created. Tsuna was smacked with the 'president' label, Kyoko became 'vice-president' and Hana the 'treasurer'. The name was also shortened to Happy Helpful Club when Haru joined.

This was all fine and dandy. Their club might be a little unconventional, and half their members didn't attend the same school (Haru was in Midori, Shōichi wasn't supposed to be at Nami-chuu, his online friend, Spanner, was given honorary membership somewhere down the line, Tsuna's penpal was also given the same treatment much to their foul-mouthed ire, Fuuta was a child and Lambo even younger) but it was relatively simple to run.

At first.

Tsuna was used to odd things happening to him; like that time his Uncle Daemon insisted Tsuna needed the _perfect_ weapon for mayhem and obligatory destruction, and secluded them in a forest somewhere in the Amazon for a month. But even _he_ questioned the logistics of how a middle school club eventually became a go-to place for replacement body doubles, information, and a sanctuary for a number of exceedingly suspicious individuals.

(Mukuro laughed _so_ hard when Tsuna, adorably befuddled, asked for his honest opinion on a question that mainly consisted of the word, ' _how_?' Shōichi looked at him like he had two heads from behind his industrial visor, Kyoko patted his head sympathetically, Haru distracted him with cake, and Fuuta ranked him as 'number one person to stumble, fall, and walk right into trouble'.

Tsuna may or may not have set the school pool on fire in frustration, much to every other student's confusion and Hibari's ire.)

Tsuna never agreed to it spreading outside school and beyond, he wasn't supposed to become this familiar with the inner workings of several enterprises, legal or not. He certainly never agreed to leading an organisation recognised on an international level.

(But alas, such was the life of one Tsunayoshi Sawada.)


	24. Chapter 24

**A/N:** Forgot a section on the previous chapter so I edited it a couple hours ago. Here's the Arcobaleno! Sorry if you're eager for more R27 scenes, I'm pretty sure there will be more chapters based on backstory than Tsuna and Reborn's relationship actually...

* * *

 _Arcobaleno, before Vongola's letter_.

"Has anyone even _heard_ from Reborn in the last year?"

Fon shook his head, as Colonnello voiced a no, and the others looked to be in the same boat.

Viper -or Mammon now, huffed in exasperation. "None of his usual contact routes are open and the Vongola Decimo's getting impatient."

"He took a break to go to University for a Masters degree," Lal said as she looked over the file Mammon had bought along. "He decided on minimal contact, so that his cover wouldn't be blown, but no contact at all? This is ridiculous."

"He contacted me." Verde interjected distractedly, eyes focused on the device he was fiddling with rather than the conversation at hand.

Mammon frowned under their hood. "Why didn't you say anything before?"

The green haired man pushed up his glasses. "He had an inane and completely stupid request."

There was a pause.

"And?" Skull prompted impatiently.

"He wanted a unicorn, what do you expect I did?"

"A _unicorn_? Did studying cause him to lose his mind, kora?"

Another pregnant pause.

"You know, he _did_ message me asking if dead people made good presents a few months back," Skull added reluctantly. "I thought he was jerking my chain like he used to, but..."

"Perhaps the mental strain has finally got to him. We are technically old people in young bodies after all," Fon said hesitantly, it was doubtful that the strongest of them would fall in such a way but it wasn't like they actually knew what was going on in the hitman's head.

"... I vote we find him, and make sure he _hasn't_ gone crazy," proposed Lal.

All the ex-Arcobaleno agreed immediately.


	25. Chapter 25

Tsuna's childhood could be described as _fulfilling_ in a way, it could also be called _pure insanity_ in another.

Not only did he have periodic play dates with Hibari Kyoya-

-Whose growing tendencies towards violence and order -of which Tsuna disturbed on frequent basis through no fault of his own (mostly)- often resulted in the little brunet being snubbed (after the last incident where Kyoya _may_ have lost his eyebrows for a month, he resolved that fighting was possibly not the best way to approach the herbivore dragon), Tsuna plaintively attempting to coax the child down the tree with the food prepared with his Mama, and Kyoya's weakening resolve to the Kasai family's cooking that could possibly entice even _demons_ into selling their souls. This often led to young Kyoya swiping the box of food and sitting reluctantly beside the other on the swing set _not_ feeling like he'd made the best accomplishment of the day as Tsuna beamed, simply happy Kyoya was there (obligatory photos were taken by Nana and Hibari's mother, laughing and sharing gossip and memories of their days in school)-

-and his uncles set up daily exercises for him and his friends, usually as entertaining games or 'adventures'.

Hana was still getting over Tsuna's apparently magic uncles who could produce illusions when she and Kyoko were introduced to an RPG (kid friendly ver.) where they got to choose their weapons and defeat 'monsters'. (Daemon took a page from the Japanese and added beady eyes and sometimes a mouth to anything he could think of, the dishwasher was a favourite) Takeshi favoured swords while Kyoko -after some experimentation with her brother's boxing style and concluding it wasn't for her, and she really _did_ like the look of that war hammer- decided that big blunt force was her thing, while Hana decided to be sensible and took on a crossbow and Tsuna, little adorable Tsuna, in a bid to emulate his uncles, decided that magic was totally his favourite weapon (Daemon was flattered, really, but he still forbade Tsuna from using any form of fire 'magic' when he was playing with his friends. As much as the child needed to learn to use his abilities, there was a _reason_ augmented reality wasn't real. Tsuna had free reign when he alone, however, and in specific _controlled_ conditions -namely, when Nana was around as damage control, or if they had enough fire extinguishers on hand.)

-The Vindice also popped by periodically to play with the child, which would have been fine if it were _just_ the rather sensible Jaeger and Bermuda.

"I am not a _babysitter_!" Daemon hissed at the two Vindice standing, almost sheepishly, at the door as he whipped back to fuss over seven year old Tsunayoshi's blood stained clothes and the toddler he was carrying. The brunet's eyes were red and he was clearly upset as he hugged the baby with flaxen brown hair closer to his chest and shifted closer against Daemon's side despite the Mist's obvious ire.

"Bringing him with you to a slave trading den, have you no _common_ sense?!"

Small Gia winced behind his bandages. **"Hey, Tsuna wanted to play hide-and-chain-seek and we had a job to do, it seemed like the perfect opportunity to get him some experience."**

The air around Daemon turned an ominous indigo. "You are _not_ grooming him to become Vindice."

 **"What- he's totally got the talent for- urk!"**

 **"Apologies for the disturbance they've caused, I will discipline these idiots,"** said Jaeger, from where he'd lifted the shorter Vindice by the collar of his cloak.

A tug on the tall Vindice's cloak had him looking down into red-rimmed amber eyes.

"It wasn't Gia and Pino's fault," Tsuna implored. "I wanted to save him and they helped me and protected me from all those people who wanted to do lots of bad things."

Jaegar continued to stare at the child as Small Gia, long since stopped struggling, waited with bated breath.

"I'll make you brownies?" Tsuna tried, amber brown eyes wide and imploring.

The straggly haired Vindici huffed and acquiesced, **"very well."** The other two Vindice's audible sighs of relief and somewhat envious stares hidden behind bandages were interrupted as he continued. **"I will have them provide an explanation to Nana-san."**

Tsuna smiled, a little smaller than usual but the gratitude was still present. Apparently satisfied with that outcome (much to Small Gia and Big Pino's loud and silent horror respectively), he turned his attention back to the toddler in his arms, cooing and rubbing cheeks with the baby boy.

Daemon knew a lost battle when he saw one, and he doubted Nana who, although undoubtedly terrifying to anyone who threatened her son, was still the kindest woman he'd ever met short of Elena, would mind an extra child in her home.

The toddler giggled, and suddenly the plain brown eyes turned dark with pinpricks of light, as if reflecting the night sky and its galaxies, and everything; from Natsu to the shoes sitting in the genkan, started floating as if gravity didn't exist.

Daemon's brow ticked. "I am not dealing with this."

There was silence as the Vindice had already disappeared and Tsuna was busy floating and admiring his new baby brother's pretty eyes.

"I am _not_ dealing with this!"

* * *

 **A/N:** i regret nothing


	26. Chapter 26

**A/N:** Chronology? What is chronology?

In response to a few reviewers, yes that was Fuuta last chapter. Have the Vindice learnt their lesson? Who knows.

(And to general zargon, thanks for spotting that mistake with "Arcolabeno' in chap 24. This is what happens when your fingers run away from you.")

now, onwards!

* * *

 _Sometime after Vongola's letter._

There were some things Reborn has learnt from his life as a hitman. There were even more from sharing space with Tsuna.

Keeping the whole Vongola thing under wraps was logical if a little difficult because some harebrained idiot up there deserved to be killed, revived and killed multiple times for leaking this out. It was a wonder Enrico survived to take over.

Reborn was not under any obligation to agree to Enrico's request let alone reply. How an assassin could find them when Vongola had no clue as to Tsuna's whereabouts spoke of incompetence to the highest degree.

Watching Tsuna despair over the bloodied floor boards was mildly entertaining, even if Reborn now had a body to deal with.

Reborn blinked as Tsuna released a frustrated groan and flung the bloodied rag onto the stained floor in disgust.

Reborn recognised that look. "Oi, Tsuna..."

The body burst into flames, instantly incinerating into ash, as did the floor boards and rag, leaving not a stain in their place as Tsuna flashed burned all evidence of a dead body.

Reborn would never admit to flinching as eyes like molten gold turned on him.

"Explain."

* * *

 **E/N:** This is why you don't keep information from Tsuna, Reborn. Just because he resembles a cinnamon roll does not mean cinnamon rolls can't incinerate you.


	27. Chapter 27

**A/N:** I'm sorry, i've been in a bad place these last few months and haven't worked up the motivation to write much.

I'm eternally grateful to hear from everyone and i laughed at the reactions to last chaper.

(And also the likes and follows, i had no idea so many people actually like reading this silly thing.)

We have the long awaited bomb boy this chapter! And swearing.

* * *

 _(Sometime after purchasing a building.)_

The Foundation's roots were in Japan, lead by a fearsome man named Kyoya Hibari.

If one had mentioned to Hayato that he'd be working on the (somewhat dubious) righteous side of the law five years ago he would have laughed his arse off and sent the fucking loon to an insanity clinic.

Hayato Gokudera was Hibari's middle school aquaintance (for they would rather suffer a grevious wound than admit to being friends) who, after exchange in Japan, made an executive decision to return to Europe and perhaps-kind of-maybe- mend his shaky relationship with his family.

Evidently, the silver haired man was still wavering over the concept.

Far be it for Hibari to miss an opportunity, and one knockdown bitten-to-death fight later and the now eighteen year old Gokudera found himself on his merry way to the UK with a recommendation and a letter addressed to some guy who he assumed was running some branch office of the Foundation. Or something.

Who knew what was going on in Hibari's fucking head?

This somewhat familiar midget with the wide eyes and overall unassuming appearance was definitely not it.

* * *

 _'He's yours now.'_ Was literally the only thing written on the letter in the neat penmanship Tsuna instantly recognised as Kyoya's.

Peering back up at the scowling silver haired young man sitting across from him in the cafeteria, Tsuna could vaguely recall him being in the class next to his back in middle school.

"Hayato, right?" Tsuna plastered on a smile even as the scowl turned to a thunderous expression of irritation.

What the hell did Kyoya get him into now?

* * *

Reborn was heading for his next class when he spotted Tsuna walking out with a dead man dogging his footsteps.

He was older and taller but that was evidently Hayato Gokudera, Bianchi's baby brother who apparently wasn't as dead as the rest of the underworld thought.

He was also an explosions specialist, last Reborn heard, following the only spontaneously combustible human Reborn knew.

Fuck.

* * *

Hayato wasn't expecting to have a nice day, what with meeting a guy who fucking _Hibari_ introduced. He actually expected some violence at some point another, given Hibari's _stellar_ record.

Which was why the sight of the greatest hitman to ever grace the underworld making for him like some fucking bat out of hell had him reaching for dynamites faster than the certified genius could think.

And Tsuna, poor Tsuna who had never outgrown his propensity to set shit on fire when startled -and it was rather startling to see entire handfuls of bombs just appear out of freaking nowhere- did just that.

Of course, he didn't set fire to the bombs in Hayato's hands, he did have _some_ control. Unfortunately the next flammable object in the proverbial list was every _other_ bomb in the bomber man's arsenal.

Hayato swore and dropped a veritable army's worth of explosives from among his clothes as he felt their wicks light. Paling at the sight of his lit arsenal.

Reborn sped up to shove Tsuna to the ground because if he was going to die he may as well die dramatically.

* * *

Fortunately, no one died. Mostly because the explosion that had been about to consume them had been _crystallised_ into some morbid sculpture of explosive flame ice.

Hayato gaped from his place on the floor, one eye millimetres from a sharp jutting piece of ice. Mind working miles a minute as he replayed what happened, because he was certain he'd been pushed. And the only one close enough to push him had been-

His eyes focused beyond the ice in his face. There was shrapnel from the casings on his dynamites, and bright spots like fireworks trapped in time, and among them was the shocked face of the short guy leaning forward in a way that would have been physically impossible, had he not been trapped in ice, hands outstretched as if reaching for Hayato. On his neck was the hand of the hitman, the rest of him was outside the ice blast, and while it was hard to see through the distortions in the ice, Hayato could just make out Reborn's wide eyed expression and his mouth moving.

"What the _fuck_ Tsuna."

Reborn startled as _warmth_ flooded into him, feather light against his heart and cosy as a worn duvet. It had been a very long time since he felt something like this, and he felt particularly stupid for not realising as he caught Tsuna's amber eyes in the ice. Ice that was very much like the one Xanxus had been trapped in years ago.

How different was Tsuna's weird fire powers from Flames? Were they fundamentally the same thing?

"H-how?" Hayato stammered, looking like he wasn't sure if he was supposed to panic because this guy just _saved_ him at the cost of trapping himself, or prostrate himself because the world's greatest hitman was staring at him in accusation. (Reborn's expression had defaulted to a blank stare in the face of his shock, but Hayato did not know that.)

A sound drew Reborn's attention to the fact that there was crack in the ice which was rapidly propagating across the surface like a demented spider's web, fragmenting his view of the brunet frozen inside. An ominous creaking sound followed until the entire thing shattered like fragile glass.

Tsuna shook off the bits of frozen flame and dynamite like a wet dog and beamed at the two dumbfounded men in front of him. "I'm good! Nothing to worry about!"

Neither one said anything.

Tsuna's expression crumpled as the silence continued, fiddling with a stray piece of starburst trapped in an ice-block awkwardly. "Uh, sorry about your dynamite?"

Another awkward silence.

"What the _fuck_ Tsuna."

* * *

 **E/N:** Reborn cannot believe his life choices has led him to dealing with Tsuna.

Hayato is torn between labelling Tsuna an UMA and stalking him to record everything from his eating habits to his underwear or regarding him with starstuck awe. (He does both.)

Tsuna will procure some dynamite for Hayato from somewhere and then have to awkwardly endure the silveret's tears of joy and reverence.


End file.
